Filter elements for liquid filters

ABSTRACT

A filter element is formed from a strip of filter paper having a regularly spaced series of transverse fold lines, two lines of adhesive being respectively applied to one edge on one face of the strip and to the opposite edge on the opposite face of the strip, the strip then being formed into pleats by folding about the transverse fold lines, the two halves of each pleat being sealed to each other at one end of the assembly but at the other end being sealed to the adjacent halves of adjacent pleats to each side thereof, so as to form a series of pockets which are open alternately at the top and the bottom of the assembly, and the ends of the assembly of pleats being sealed to each other to form it into a hollow tubular element which may then be fitted into a housing with a center tube and end plate assembly, the element being sealed at one end to the housing and at the other end to the center tube.

[ 51 May 16, 1972 FILTER ELEMENTS FOR LIQUID FILTERS Derrick PercivalTuffnell; Stanley William Kemp, both of Southampton, England inventors:

Assignee: General Motors Corporation, Detroit,

Mich.

Jan. 25, 1971 Filed:

Appl. No.:

Foreign Application Priority Data Jan. 28, 1970 Great Britain ..4,070/70U.S. Cl ..2l0/439, 210/444, 210/451, 210/493 Int. Cl ..B0ld 27/06 Fieldof Search ..55/497-500, 510, 55/511, 521; 210/435-444, 451, 493, 497

References Cited UNITED STATES PATENTS Ericson ..2l0/439 Jackson et a1..55/497 X Bub ..55/52l X 3,487,625 1/1970 Lucas ..2l0/493 X 3,502,2183/1970 Tufinell et al ..2l0/443 X F ORElGN PATENTS OR APPLICATIONS1,188,525 4/1970 Great Britain ..2l0/493 Primary Examiner-ReubenFriedman Assistant Examiner-R. W. Burks Attorney-Sidney Carter and PeterA. Taucher 57 ABSTRACT A filter element is formed from a strip of filterpaper having a regularly spaced series of transverse fold lines, twolines of adhesive being respectively applied to one edge on one face ofthe strip and to the opposite edge on the opposite face of the strip,the strip then being formed into pleats by folding about the transversefold lines, the two halves of each pleat being sealed to each other atone end of the assembly but at the other end being sealed to theadjacent halves of adjacent pleats to each side thereof, so as to form aseries of pockets which are open alternately at the top and the bottomof the assembly, and the ends of the assembly of pleats being sealed toeach other to form it into a hollow tubular element which may then befitted into a housing with a center tube and end plate assembly, theelement being sealed at one end to the housing and at the other end tothe center tube.

4 Claims, 7 Drawing Figures I? P i FILTER ELEMENTS FOR LIQUID FILTERSThis invention relates to filter elements for liquid filters and inparticular to filter elements, and filter units including such filterelements, for use in the filtration of liquid fuels for internalcombustion engines.

A filter element according to the present invention is formed from astrip of sheet filter material having two lines of adhesive respectivelyapplied to opposite faces of the strip adjacent opposite longitudinaledges thereof, the strip being folded about a series of regularly spacedtransverse fold lines to form an assembly of accordian pleats, the twohalves of each pleat being sealed to each other, at one end of theassembly, and, at the other end of the assembly, being sealedrespectively to the adjacent halves of adjacent pleats to each sidethereof.

The ends of the assembly of pleats thus formed may be secured and sealedto each other to form the assembly into a hollow tubular filter element.

In order to form a filter unit which may be readily fitted into a fuelfilter of known kind, in which a hollow tubular element is clampedbetween a filter head and a bowl for the collection of water dropletswhich have separated out from the fuel during filtration, the tubularfitted element may be fitted over the central hollow spigot of acombined center tube and end plate assembly which is conveniently formedof plastics, comprising an annular end plate with a central flangedopening adapted to be fitted over a spigot in a filter head and a centertube which extends coaxially from one face of the end plate and isintegral therewith. The filter element fits over the center tube and atits inner periphery is sealed by adhesive to the angle between the endplate and center tube, the free ends of the pleats at that end being atthe outer periphery of the element.

The center tube and end plate with the filter element fitted thereon isthen inserted in a tubular casing or shell having a base with an annularinternal shoulder thereon on which the other end of the filter elementis seated, the outer periphery of the element at that end being sealedto the annular shoulder by adhesive.

The casing is conveniently made of sheet metal and the base thereof hasa central aperture and is formed with a neck which locates the free endof the center tube. The base is spaced by the annular shoulder from theother end of the filter element and is formed with a plurality ofopenings therein.

The end plate is sealed at its outer periphery to the wall of thecasing.

It will be understood that with the construction of the filter elementdescribed the positions of the seals between the ends of the element andthe casing and center tube and end plate will be reversed if theposition of the filter element is reversed end for end relative to theend plate and center tube.

In use the filter unit formed as described above is clamped between aseat on a filter head and an annular seat on a cup or like containerwhich is secured to the filter head by a bolt passing coaxially throughthe cup and filter head. The filter head has a central spigot with anannular gasket located in an external groove therein, the end plate ofthe filter unit fitting over and being sealed to the central spigot ofthe filter head.

The scope of the invention is defined by the appended claims; and theinvention and the method by which it is to be performed are hereinafterparticularly described with reference to the accompanying drawings inwhich:

FIG. 1 is a plan of a strip of sheet filter material in the course ofits formation into a filter element in accordance with the invention;

FIG. 2 is a view on the line II-II of FIG. 1;

FIG. 3 is a section on the line III-III of FIG. 1;

FIG. 4 is a perspective view showing a portion of a filter element inaccordance with the invention;

FIG. is a composite vertical section through a fuel filter assemblyincorporating a filter element according to the invention, the left handside of the drawing showing liquid flow through the assembly from apassage in the filter head to the top of the filter unit, through theelement, and then to a central passage in the filter unit, and the righthand side showing liquid flow from the central passage in the filterunit, through the element, and then from the upper end of the element toa passage in the filter head;

FIG. 6 is a vertical section of a modified form of the filter unit shownin FIG. 5; and

FIG. 7 is a plan of FIG. 6.

Like parts in the drawings bear similar reference numerals.

In order to form a filter element according to the invention a strip 1of filter paper, which may be crepe paper impregnated with syntheticresin, or containing synthetic resin incorporated in the paper duringits manufacture, or may be synthetic resin impregnated filter paper, isused. The paper strip 1 has a line of adhesive 2 applied to one facethereof along one longitudinal edge of the strip 1, and a further lineof adhesive 3 applied to the opposite face of the strip adjacent theopposite longitudinal edge thereof. The strip is then folded aboutregularly spaced transverse fold lines 4 to form an assembly ofaccordian pleats 5, the two halves of each pleat being sealed to eachother, at one end of the assembly, and, at the other end of the assemblybeing sealed respectively to the adjacent halves of adjacent pleats toeach side thereof, as shown in FIGS. 1, 2 and 3.

The paper may have spacer dimples or other spacer formations impressedtherein, as is known in the art, to space adjacent pleats, and the twohalves of each pleat, from each other, but such formations are omittedfrom the drawing for the sake of clarity.

The ends of the strip thus formed into an assembly of pleats may besecured and sealed to each other to form the assembly into a hollowtubular filter element 6, as shown in FIG. 4.

FIG. 5 shows the manner in which the filter element 6 is formed into afilter unit 7 which is fitted into a fuel filter of known kind, thefilter unit 7 being clamped between a filter head 8 and a bowl 9 for thecollection of water droplets which have separated out from the fuelduring filtration, the tubular filter element 6 being fitted over acentral tube 10 which is integral with a coaxial end plate 11 and formsa combined center tube and end plate assembly which is conveniently madeof plastics, the end plate 11 being of annular form and having a centralopening around which extends a flange 12 which is adapted to fit over acentral hollow spigot 14 in the filter head 8 and is sealed thereto byengagement with a seal ring 15 located in an annular recess in the outerperiphery of the spigot 14.

The filter element 6 fits over the center tube 10 and at its innerperiphery is sealed by adhesive 16 to the angle between the end plate 11and center tube 10, the free ends of the pleats of the element 6 at thatend being at the outer periphery of the element.

The center tube 10 and end plate 11 with the filter element 6 fittedthereon is arranged within a tubular casing or shell 17 having a base 18with an annular internal shoulder 19 thereon on which the other end ofthe filter element 6 is seated, the outer periphery of the element 6 atthat end being sealed to the annular shoulder 19 by adhesive 20.

The casing 17 is conveniently made of sheet metal and the base 18thereof has a central aperture and is formed with a coaxial neck 21which locates the free end of the center tube 10. The base 18 is spacedby the annular shoulder 19 from the other end of the filter element 6and is formed with a plurality of lanced openings 22 therein.

The end plate 11, at its outer periphery, is sealed, as by adhesive, tothe wall of the casing 17.

It will be understood that with the construction of the filter unit 7described the positions of the seals 16 and 20 between the ends of theelement 6 and the casing 17 and center tube 10 will be reversed (asshown in FIG. 6) if the position of the filter element 6 is reversed endfor end relative to the end plate 11 and center tube 10.

In use, the filter unit 7 formed as described above is clamped betweenan annular seat 24 on the filter head 8 and an annular seat 25 at theopen end of the bowl 9 which is secured to the filter head 8 by a bolt26 passing coaxially through the bowl 9 and filter head 8. The filterunit 7 is sealed to the spigot 14 by the seal ring 15, and gaskets 27and 28 are interposed respectively between the upper end of the filterunit 7 and the seat 25 and the lower-end of the filter unit and the seat25. v

The end plate 11 has therein openings 21 which overlie the spacesbetween the ends of the pleats of the filter element 6 and are incommunication with an inlet passage 32 in the filter head, the spacewithin the center tube 10 being in communication with an outlet passage33 in the head by way of the hollow spigot 14.

In use liquid, for example fuel to be filtered, is delivered through thefilter head 8 to the spaces between the sealed ends of the pleats atthat end of the element 6. At the other end of the element 6 the spacesbetween the pleats are closed, the two halves of the pleats to each sideof said spaces being sealed to each other, and the liquid is thereforecompelled to pass through the material of the pleats to each side ofsaid spaces and then to pass between the spaces of the pleats at theinner periphery of the element 6 at said other end and from thence tothe openings 22 in the annular base 18 of the filter casing 17 into thebowl 9 where water droplets which have been formed as the liquid fuelpasses through the filter paper settle out at the base of the bowl, thefiltered liquid passing upwardly through the center tube and thence tothe outlet opening 33 in the filter head 8, This flow path is indicatedby the arrows on the left hand portion of FIG. 5.

With the arrangement described the direction of flow of the liquid canbe reversed, the liquid to be filtered then being delivered through thecenter tube 10 and then passing through the openings 22 in the base ofthe casing 17 of the filter unit 7, then through the spaces between thepleats at the lower end of the element 6, through the walls of thepleats and then through the spaces between the pleats at the upper endof the element, through the openings 31 in the end plate 11 and then outthrough the passage 32 to filter head 8.

The construction described above has the desirable advantages that thefilter can be used with liquid flow in either direction through theelement and that the filter can be readily bled to get rid of airtherein before operation.

The casing, center tube and end plate may be formed in sheet metal.

If the center tube has to extend the full length of the filter and thewidth of the element is not such as to occupy the space between thecenter tube and easing the modified form of construction of the filterunit 7 shown in FIGS. 6 and 7 may be employed. In this form of thefilter unit, (which is shown with its end plate and center tube made ofsheet metal but which could also be made with an end plate and centertube of plastics) the unit 7 is provided with two center tubes one 10 ofwhich, similarly to the center tube shown in FIG. 5, is engaged by andsupports the inner periphery of the element 6, and the other, 51 ofwhich is secured at its ends to the inner periphery of the annular endplate 11 and the inner periphery of the base 18 of the casing 17. Theend plate 11 preferably has interconnected radial and annular channels52, 53 embossed therein which provide communication between the holes 31in the end plate 11 and the space between the two center tubes 10, 51 sothat air therein can be vented by way of the channels 52, 53 and holes31 when the filter 6 is bled to expel air therefrom.

We claim:

1. Aifilter unit comprising a filter element formed from a strip ofsheet filter material having two lines of adhesive respectively appliedto opposite faces of the strip adjacent opposite longitudinal edgesthereof, the strip being folded about a series of regularly spaced foldlines extending transversely of the strip to form an assembly ofaccordion pleats, the two halves of each pleat being sealed to eachother, at one end of the pleat, and, at the other end thereof, beingsealed respectively to the adjacent halves of adjacent pleats to eachside thereof, and the ends of said strip being secured and sealed toeach other to form the assembly into a hollow tubular filter element; acombined center tube and end plate assembly having an annular end platewith a central flanged opening adapted to be fitted over a spigot in afilter head, and a center tube which extends coaxially from one face ofsaid end plate; and a tubular casing having at one end thereof acentrally apertured base with an annular internal shoulder thereonadjacent the wall of the casing, said filter element being fitted oversaid center tube and sealed at its inner periphery at one end thereof tothe angle between the end plate and center tube, the free ends of thepleats adjacent said one end being at the outer periphery of theelement, and the assembled filter element, end plate and center tubebeing fitted within said casing with the other end of said elementseated on said internal shoulder, the outer periphery of the element atsaid other end being sealed to the annular shoulder, and the outerperiphery of said end plate being sealed to the casing at the other endthereof.

2. A filter unit according to claim 1, in which said end plate hasopenings therein overlying the ends of said pleats.

3. A filter unit according to claim 2, in which said casing base isformed with openings therein.

4. A filter unit according to claim 1, in which said center tube fitswithin and is sealed to said base, said end plate and base havingopenings therein adjacent the ends of said pleats of the element, saidelement being spaced at its inner periphery from said center tube andsaid end plate being formed with impressed channels providingcommunication between the openings in said end plate and the spacebetween the center tube and the element.

1. A filter unit comprising a filter element formed from a strip ofsheet filter material having two lines of adhesive respectively appliedto opposite faces of the strip adjacent opposite longitudinal edgesthereof, the strip being folded about a series of regularly spaced foldlines extending transversely of the strip to form an assembly ofaccordion pleats, the two halves of each pleat being sealed to eachother, at one end of the pleat, and, at the other end thereof, beingsealed respectively to the adjacent halves of adjacent pleats to eachside thereof, and the ends of said strip being secured and sealed toeach other to form the assembly into a hollow tubular filter element; acombined center tube and end plate assembly having an annular end platewith a central flanged opening adapted to be fitted over a spigot in afilter head, and a center tube which extends coaxially from one face ofsaid end plate; and a tubular casing having at one end thereof acentrally apertured base with an annular internal shoulder thereonadjacent the wall of the casing, said filter element being fitted oversaid center tube and sealed at its inner periphery at one end thereof tothe angle between the end plate and center tube, the free ends of thepleats adjacent said one end being at the outer periphery of theelement, and the assembled filter element, end plate and center tubebeing fitted within said casing with the other end of said elementseated on said internal shoulder, the outer periphery of the element atsaid other end being sealed to the annular shoulder, and the outerperiphery of said end plate being sealed to the casing at the other endthereof.
 2. A filter unit according to claim 1, in which said end platehas openings therein overlying the ends of said pleats.
 3. A filter unitaccording to claim 2, in which said casing base is formed with openingstherein.
 4. A filter unit according to claim 1, in which said centertube fits within and is sealed to said base, said end plate and basehaving openings therein adjacent the ends of said pleats of the element,said element being spaced at its inner periphery from said center tubeand said end plate being formed with impressed channels providingcommunication between the openings in said end plate and the spacebetween the center tube and the element.